losetup -f
losetup /dev/loop0 /home/tk/build/output/images/Armbian_5.46_Tinkerboard_Debian_stretch_next_4.14.47.img
partprobe /dev/loop0
mount /dev/loop0p2 /mnt/new-rootfs/
wget -O /mnt/new-rootfs/etc/fstab https://raw.githubusercontent.com/ThomasKaiser/OMV4_for_Raspberries/master/overlay/fstab
losetup -f
losetup /dev/loop1 /home/tk/OMV_4_Raspberry_Pi_2_3_3Plus.img
partprobe /dev/loop1
mkfs.ext4 -q -m 2 /dev/loop1p2
tune2fs -o journal_data_writeback /dev/loop1p2
mount /dev/loop1p2 /mnt/omv4/
rsync -arltD --stats /mnt/new-rootfs/ /mnt/omv4
chmod 755 /mnt/omv4
dd if=/dev/zero of=/mnt/omv4/lala bs=1M || (sync ; rm /mnt/omv4/lala)
umount /mnt/omv4/
losetup -d /dev/loop1